Lesson C2–8



ANIMAL HEALTH

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Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 1

Student Learning Objectives. Instruction in this lesson should result in students achieving the following objectives:

1 Find and time a pulse on a dog and understand what sound makes a “heartbeat”.

2 Be able to successfully give a physical exam and listen to heart, lungs, and observe the overall condition of the dog and be able to recognize signs of an unhealthy or stressed animal (i.e., elevated or depressed temperature, erratic heart rate, irregular breathing, pale gums, etc.).

Anticipated Problem: How do we find and time the pulse on a dog and what sound makes a “heartbeat”?

I. The pulse of an animal is the rhythmic expansion of an artery which may be felt with a finger. The pulse correlates with the heart rate (how quickly the heart is beating) of the animal.

A. To find the pulse rate of a dog, feel caudal and dorsal to the elbow of a standing dog. The pulse can also be felt on the inside of the dog’s thigh, about level with the knee. Count the number of beats in one minute (or the number of beats in 15 seconds and multiply by 4). This is the dog’s resting pulse, or heart rate.

B. The pulse happens at the same rate as the beating of the heart because the heart is pumping the blood. As more blood is pumped, the arteries expand and blood is cycled back to the heart.

C. The sound of a heartbeat is caused by the opening and closing of the valves of the heart. Because the heart is a muscle and is contracting to pump blood to the body, there is considerable force closing the valves of the heart. There are two valves that separate the

chambers of the heart and give off the “lub-dub” sound that can be heard with a stethoscope, an instrument for listening to internal body sounds.

Anticipated Problem: How do we give a physical exam and listen to the heart, lungs, and observe the overall condition of a dog? What are the signs of an unhealthy or stressed animal?

II. Giving a physical exam to a dog requires observation of the pulse, respiration rate, temperature, and capillary refill time (CRT).

A. The pulse can be taken from the inside of the thigh or elbow of the dog. Please refer to

the procedures outlined in objective 1.

B. The respiration rate, or number of breaths per minute, can be calculated by simply

counting the number of breaths the animal takes in one minute (or counting for 15 seconds and multiplying by 4). Respiration can also be found by holding a stethoscope to

the dog’s chest to listen to lung sounds. Respiration rate will decrease as the animal size

increases. A normal respiration rate for a dog would be approximately 22 breaths per

minute. A sign of an unhealthy animal would be rapid and shallow breathing or

extremely slow respiration.

C. The temperature of the dog must be taken with a rectal thermometer. Dogs could

become agitated and bite down on a thermometer inserted into the mouth. When using

a rectal thermometer, insert the thermometer 1.5 to 2 inches into the rectum of the animal

and leave it for one minute. The normal temperature range for a dog is 101 to

102.5°F. Unhealthy animals, like humans, will run a temperature if they are fighting an

illness.

D. Capillary Refill Time (CRT), is an indication of how quickly blood will refill the capillaries of body tissues. To check CRT, raise the upper lip of the dog and press on the gum and release. In a healthy animal, the gum will turn white and then pink again.

Unhealthy animals will have a CRT of longer than 3 seconds. Animals with CRT of

more than 3 seconds could be exhibiting signs of shock.

E. An overall check of animal health is also important during a checkup. Things to observe in an overall check would be dog behavior (excited?, wagging tail?, lethargic?), coat condition (shiny or dull?), eye condition (bright eyes or dull?, responsive to activity?), and teeth condition (white, clean, strong teeth?, healthy gums?).

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 4

Anticipated Problem: What are common diseases found in pets and livestock animals?

III. Diseases can be defined as some disturbance of normal body functions or structures. Some diseases are specific to a certain type of animal or livestock. Most diseases can be controlled with a vaccination, or injection of a disease fighting medicine. Some vaccinations are actuallyvlow doses of the disease itself, allowing the body to fight the disease and build up a resistance for the next exposure to the disease.

A. Diseases can either be contagious, able to be spread to other animals, or non-contagious, unable to be spread to others. Contagious diseases are caused by viruses, bacteria, fungi, protozoa, and parasites. Non-contagious diseases can be caused by nutrient deficiencies, body defects, animal injuries, and genetics.

B. Some selected common diseases of livestock are listed below.

1. Anthrax—An infectious disease that will attack most warm-blooded animals. Can

affect cattle during summer when they are on pasture.

2. Brucellosis—An infectious disease of the reproductive tract of cattle, sheep, goats,

hogs, and can be spread to humans. Also known as ‘Bang’s’, this disease causes

developing fetuses to abort and can be fatal.

3. Hog Cholera—A highly contagious viral disease of swine that can be fatal. There is

no known treatment for cholera and all swine with cholera must be destroyed.

4. Coccidiosis—A parasitic disease affecting poultry that can be treated with a medication in the feed and water. Birds must be isolated for treatment.

5. Sleeping Sickness—A virus in horses caused from insect bites. Symptoms include

reckless walking, sleepy appearance, cannot swallow, and grinding of teeth. Most

horses die within two to four days, but some can recover with treatment.

6. Foot and Mouth—A disease that only affects animals with cloven or divided feet.

Caused by a virus, it is highly contagious and has no known treatment at this time.

Infected animals get watery blisters around the mouth and skin of the foot.

7. Mastitis—A bacterial disease that affects female cattle, sheep, goats, and swine. An

inflammation of the udder that interferes with milk production. Although treatable,

chronic mastitis can lead to death of the animal. Milk from a diseased animal cannot

be sold for consumption or any use.

8. Rabies—An infectious disease that can occur in nearly every warm-blooded animal.

Caused by a virus, this disease can be spread to humans. Affected animals may

become “crazed” or exhibit aggressive behavior, as well as other symptoms.

Although treatment is available for humans, animals with rabies are destroyed and

autopsied to diagnose the disease.

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 5

ANIMAL HEALTH

_ Part One: Matching

Instructions: Match the term with the correct response.

a. Pulse d. Contagious g. Vaccination

b. Disease e. Capillary Refill Time h. Respiration Rate

c. Stethoscope f. Non-Contagious

_______1. A disturbance of body functions or structures.

_______2. Diseases caused by injury, nutrition, or genetics.

_______3. The number of breaths an animal takes in one minute.

_______4. A device used to listen to internal sounds of the body.

_______5. An indication of the blood flow to tiny blood vessels.

_______6. The expansion of an artery due to blood flow from a heartbeat.

_______7. A type of injection to prevent or treat a disease.

_______8. Diseases caused by viruses, bacteria, and fungi.

Part Two: Completion

Instructions: Provide the word or words to complete the following statements.

1. When taking the temperature of a dog, it is important to use a ________ thermometer.

2. Slow capillary refill time can be an indication that the animal is going into ______.

3. The ‘heartbeat’ sound is caused by opening and closing of heart _________.

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 8

Part Three: Multiple Choice

Instructions: Circle the letter of the correct answer.

_______1. The gums of an animal are often used to check _________________.

a. heart rate

b. pulse

c. capillary refill

d. breathing

_______2. What instrument can be used to listen to the heart beat of an animal?

a. thermometer

b. stethoscope

c. blood pressure cuff

d. tourniquet

_______3. Which of the following would be a sign of a stressed or unhealthy animal?

a. pale gums

b. regular heartbeat

c. wagging tail

d. shiny coat

_______4. If pale gums are noted on a horse, one could expect what condition?

a. shock

b. poor nutrition

c. normal health

d. none of the above

_______5. Mastitis is an inflammation of the _________ in cattle.

a. teeth

b. udders

c. gums

d. feet

_______6. Rabies can occur in

a. dogs

b. cattle

c. raccoons

d. all of the above

_______7. Sleeping sickness is a disease most commonly found in _________.

a. horses

b. sheep

c. swine

d. dogs

_______8. The disease that infects the reproductive tract of animals and may cause death of unborn fetuses is ______________.

a. rabies

b. hog cholera

c. Foot and Mouth

d. Brucellosis

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 9

Part Four: Short Answer

Instructions: Provide information to answer the following questions.

1. Pretend you are a veterinarian giving an overall health check up to a dog. What are four specific signs of good health you would look for in this animal?

2. Discuss the difference between contagious and non-contagious disease and give one specific disease for each.

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 10

Assessment

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 23

TS–A

Technical Supplement

ANIMAL HEALTH

1. Why would the heart rate and pulse be the same?

Heart rate is determined by the number of times per minute that the heart undergoes

a rhythmic contraction to pump blood through the circulatory system. With

each "beat" of the heart, blood is pumped into arteries causing the muscle of the

artery to expand to accept the increased pressure and flow of blood. As the blood

moves, forward through the arteries, the expansion of the artery is reduced until the

next heart beat. This rhythmic expansion and contraction of the arteries is known as

the pulse and can be felt at various external locations on the animal's body. Since

pulse can only be felt when the heart contracts to pump blood through the arteries,

the heart rate and pulse will be the same. Pulse is often used to determine the heart

rate of an animal and is one of the vital signs used to assess the health and vigor of the

animal.

2. What are some things that could raise a dog's heart rate?

When assessing the health of an animal, such as a dog, an abnormal heart rate could

either increase or decrease the pulse. A recent increase in activity or exercise, excitement,

anger, or fear would cause the normal heart rate to increase, yet would not

normally indicate any related health problems. However, an increase in the animal's

body temperature often results in an increase in heart rate and could indicate disease,

infections, or other related health concerns. Also, severe shock or stress often

results in a lower heart rate. Loss of blood, either externally or internally, can lower

the pulse. Some medications have also been known to affect the normal heart rate of

the animal.

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 24

3. Why is there such a large range on heart rate and pulse in dogs?

While the heart rate in most species of animals will be very consistent from one animal

to another, the range in pulse for dogs may vary from 100 to 130 beats per minute.

This wide range is mostly due to the large differences in weight and size of the

various breeds of dogs. The smaller breeds of dogs will have a higher heart rate than

larger breeds. Younger and more immature animals will also have a higher heart rate

than the older adult animals.

4. What signs should you look for when pale gums are discovered?

Capillary refill time (CRT) is sometimes used along with vital signs to assess an animal's

health and vigor. Capillaries are minute blood vessels lacking muscular walls

that disperse blood to the individual cells and connect the arteries and veins. When

tissue is placed under pressure from a thumb or finger, blood is forced out of the

capillaries in that spot. When the pressure is removed, one to three seconds is normally

required for blood to refill the capillaries and for the normal pink color to

return to the area. If the CRT time is longer than this, the animal may be experiencing

health related problems. The gums of the animal are often used to test the CRT.

If pale gums are noted, the animal could be suffering from shock. One should

immediately check other vital signs of heart rate, body temperature, and respiration

rate to further identify potential problems. Loss of blood often causes shock and one

should check for external bleeding. If none is noted, there is a possibility that internal

bleeding is occurring. Signs of physical injury, abnormal movement, stance or

posture, the level of the animal's consciousness to its surroundings, and the overall

color and physical appearance of the animal should also be checked for unusual

signs.

Illinois Biological Science Applications in Agriculture Lesson C2–8 • Page 25

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